Abstract

Fluid flow in reservoir rock is a function of rock permeability, so there is a relationship between flow from the wellbore to the reservoir and vice versa. This relationship is also affected by the fluid characteristics and phases. For geothermal fields the relationship is unique.

For the geothermal well, the flow of fluid from the wellbore to the reservoir is monitored by conducting a completion test in order to predict reservoir characteristics such as transmissivity (kh) and injection rate. The production test is performed after the well has been heated up by discharging the well through a vertical or horizontal pipe. The rate of production is usually calculated using the lip pressure formula.

The accuracy of production test result depends on the size of production facilities, such as the diameter of the discharge pipe and the size of the separator or silencer.

Kamojang Field is a vapour dominated reservoir system. Statistical data shows that the relationship between completion test data follows a certain curve. Based on the curve, the proper size production facilities can estimated in order to obtain good test results.